first add files

lib/Crypto/Cipher/ChaCha20_Poly1305.pyi

@@ -0,0 +1,28 @@
+from typing import Union, Tuple, overload
+
+Buffer = Union[bytes, bytearray, memoryview]
+
+class ChaCha20Poly1305Cipher:
+    nonce: bytes
+
+    def __init__(self, key: Buffer, nonce: Buffer) -> None: ...
+    def update(self, data: Buffer) -> None: ...
+    @overload
+    def encrypt(self, plaintext: Buffer) -> bytes: ...
+    @overload
+    def encrypt(self, plaintext: Buffer, output: Union[bytearray, memoryview]) -> None: ...
+    @overload
+    def decrypt(self, plaintext: Buffer) -> bytes: ...
+    @overload
+    def decrypt(self, plaintext: Buffer, output: Union[bytearray, memoryview]) -> None: ...
+    def digest(self) -> bytes: ...
+    def hexdigest(self) -> str: ...
+    def verify(self, received_mac_tag: Buffer) -> None: ...
+    def hexverify(self, received_mac_tag: str) -> None: ...
+    def encrypt_and_digest(self, plaintext: Buffer) -> Tuple[bytes, bytes]: ...
+    def decrypt_and_verify(self, ciphertext: Buffer, received_mac_tag: Buffer) -> bytes: ...
+
+def new(key: Buffer, nonce: Buffer = ...) -> ChaCha20Poly1305Cipher: ...
+
+block_size: int
+key_size: int